Communication system for alleviating interference arising due to coexistence

ABSTRACT

A communication apparatus is disclosed, which comprises a base station module and an access point module for providing wireless connectivity to a communication network to at least one mobile communication device; an interface for coupling the base station module and the access point module for performing at least one of: a channel restriction operation; a power restriction operation; an intelligent uplink scheduling operation; a carrier frequency reselection operation; and a traffic steering operation; whereby alleviating an interference arising due to coexistence of the base station module and the access point module.

The present application is a Continuation application of Ser. No.15/316,927 filed on Dec. 7, 2016, which is a National Stage Entry ofPCT/JP2015/067377 filed on Jun. 10, 2015, which claims priority fromUnited Kingdom Patent Application 1410538.1 filed on Jun. 12, 2014, thecontents of all of which are incorporated herein by reference, in theirentirety.

TECHNICAL FIELD

The present invention relates to radio access networks in a cellular orwireless telecommunication network, and particularly but not exclusivelyto networks operating according to the 3GPP standards or equivalents orderivatives thereof. The invention has particular although not exclusiverelevance to the Long Term Evolution (LTE) of UTRAN (called EvolvedUniversal Terrestrial Radio Access Network (E-UTRAN)) and to operationof dual mode base stations operating in accordance with both LTE andnon-LTE radio technologies.

BACKGROUND ART

In a cellular communication network, mobile devices (also known as UserEquipment (UE) or mobile terminals, such as mobile telephones)communicate with remote servers or with other mobile devices via basestations. An LTE base station is also known as an ‘enhanced NodeB’(eNB), which is coupled to an LTE core network also known as an EnhancedPacket Core (EPC) network.

In their communication with each other, LTE mobile devices and basestations use licensed radio frequencies, which are typically dividedinto frequency bands and/or time blocks. Depending on various criteria(such as the amount of data to be transmitted, radio technologiessupported by the mobile device, expected quality of service,subscription settings, etc.), each base station is responsible forcontrolling the transmission timings, frequencies, transmission powers,modulations, etc. employed by the mobile devices attached to the basestation. In order to minimise disruption to the service and to maximiseutilisation of the available bandwidth, the base stations continuouslyadjust their own transmission power and also that of the mobile devices.Base stations also assign frequency bands and/or time slots to mobiledevices, and also select and enforce the appropriate transmissiontechnology to be used between the base stations and the attached mobiledevices. By doing so, base stations also reduce or eliminate any harmfulinterference caused by mobile devices to each other or to the basestations.

Current mobile devices typically support multiple radio technologies,not only LTE. The mobile devices might include, for example,transceivers and/or receivers operating in the Industrial, Scientificand Medical (ISM) radio bands, such as Bluetooth or Wi-Fi transceivers.The term ‘Bluetooth’ refers to the standards developed by the BluetoothSpecial Interest Group, and the term ‘Wi-Fi’ refers to the 802.11 familyof standards developed by the Institute of Electrical and ElectronicsEngineers (IEEE). If such a non-LTE communication technology issupported, instead of communicating via LTE base stations, mobiledevices may also communicate with remote servers or with other mobiledevices using non-LTE communication means, e.g. using an appropriate ISMcommunication technology. For example, the mobile devices maycommunicate via an access point (e.g. a Wi-Fi AP) operating inaccordance with the 802.11 family of standards by the Institute ofElectrical and Electronics Engineers (IEEE).

Recently, a so-called ‘dual mode’ base station has been introducedcomprising an LTE home base station (HeNB) part (e.g. a pico/femto basestation or other low-power node) and a non-LTE access point part (e.g. aWi-Fi AP). Such a combined HeNB/AP base station may also sometimes bereferred to as a dual mode femto access point (FAP) or dual FAP.

ISM and other radio technologies (hereafter commonly referred to asnon-LTE technologies) use frequency bands close to or partiallyoverlapping with the LTE frequency bands, as illustrated in FIG. 12.Some of these non-LTE frequency bands are licensed for a particular use(e.g. Global Positioning Systems (GPS) bands) or might be unlicensedbands and can be used by a number of radio technologies (such asBluetooth and Wi-Fi standards using the same range of ISM frequencybands). The manner in which these non-LTE frequency bands are used are,therefore, not covered by the LTE standards and are not controlled bythe LTE base stations (e.g. a HeNB of a dual FAP). However,transmissions in the non-LTE frequency bands might, nevertheless, stillcause undesired interference to (or suffer undesired interferenceresulting from) transmissions in the LTE bands, particularly in theoverlapping or neighbouring frequency bands.

In particular, such undesired interference may be experienced betweenLTE and non-LTE (ISM) radio communications in at least the followingscenarios:

-   -   LTE Band 40/41 radio transmitter causing interference to ISM        radio receiver;    -   ISM radio transmitter causing interference to LTE Band 40/41        radio receiver;    -   LTE Band 7 radio transmitter causing interference to ISM radio        receiver;    -   ISM radio transmitter causing interference to LTE Band 7 radio        receiver; and    -   LTE Band 7/13/14 radio transmitter causing interference to GPS        radio receiver.

When such undesired interference arises as a result of communicationoccurring concurrently in the same mobile device or in the same basestation (for example, as a result of concurrent use of LTE and non-LTEradio technologies) the interference is sometimes referred to as‘in-device coexistence (IDC) interference’ which causes an ‘in-devicecoexistence (IDC) situation’.

In order to be able to alleviate the problems due to IDC interference,the mobile device may be configured to attempt to address such IDCproblems on its own and, if the mobile device cannot solve the problemon its own, with the assistance of its serving base station. Forexample, an IDC problem may be addressed by the base station selecting adifferent frequency (FDM solution) for the mobile device, byreconfiguring its transmissions (e.g. apply discontinuous reception(DRX) and/or change its subframe pattern) (TDM solution), and/or byadjusting the base station's (and/or the mobile device's) transmissionpower (Power Control solution).

The inventors have realised that difficulties may arise insimultaneously operating both the LTE and non-LTE parts of such dualFAPs due to the potentially severe interference experienced in some ofthe (neighbouring or overlapping) frequency bands used by both the LTEand the non-LTE communication technologies.

Such difficulties are particularly likely to occur with respect to dualFAPs implementing both an LTE base station and a non-LTE access point aspart of the same network node. In this case, the above (FDM/TDM/PowerControl) solutions are not always applicable because any change in theoperation of the LTE base station (of the dual FAP) may still cause (orcontinue to cause) unexpected interference for communications using theaccess point part of the dual FAP.

The inventors have also realised that whilst it is possible toco-ordinate some of the operations of LTE base stations and other basestations operating in accordance with an earlier standard from which LTEhas been derived, e.g. due to the inherent backward compatibilitybetween such related standards, it is particularly difficult to ensureoptimal communication characteristics (e.g. signal quality, error rate,interference level) for dual FAPs implementing both an LTE base stationand a non-LTE access point because of the differences between theoperation of the LTE and the non-LTE parts.

SUMMARY OF INVENTION

There is therefore a need to improve the operation of the mobile deviceand the dual FAP in order to overcome or at least alleviate the aboveproblems. Exemplary embodiments of the present invention aim to provideimproved techniques for alleviating interference (hence improving datathroughput) in a communication network and, in particular, foralleviating radio interference caused to, or by, transmissions via adual FAP (and/or the like).

In one aspect, the invention provides a communication apparatuscomprising: a base station module for providing wireless connectivity ina communication network, using a first communication protocol, to atleast one mobile communication device; an access point module forproviding wireless connectivity in a communication network, using asecond communication protocol, to the at least one mobile communicationdevice; and an interface for coupling the base station module and theaccess point module, wherein said interface is configured forcommunication between said base station module and said access pointmodule; wherein said base station module and said access point moduleare configured for co-operation with one another by communicating viasaid interface, and wherein at least one of said base station module andsaid access point module is configured to perform at least one operationto alleviate interference arising due to coexistence, in saidcommunication apparatus, of said base station module and said accesspoint module, as part of said co-operation.

In one aspect, the invention provides a method performed by acommunication apparatus comprising: i) a base station module forproviding wireless connectivity, using a first communication protocol,in a communication network to at least one mobile communication device;ii) an access point module for providing wireless connectivity, using asecond communication protocol, in a communication network to the atleast one mobile communication device; and iii) an interface forcoupling the base station module and the access point module, whereinsaid interface is configured for communication between said base stationmodule and said access point module; the method comprising: the basestation module and the access point module co-operating with one anotherby communicating via said interface, and at least one of said basestation module and said access point module performing at least oneoperation to alleviate interference arising due to the coexistence, insaid communication apparatus, of said base station module and saidaccess point module, as part of said co-operating.

In one aspect, the invention provides a system for use in atelecommunication network, comprising one or more mobile communicationdevices and the above described communication apparatus.

Aspects of the invention extend to computer program products such ascomputer readable storage media having instructions stored thereon whichare operable to program a programmable processor to carry out a methodas described in the aspects and possibilities set out above or recitedin the claims and/or to program a suitably adapted computer to providethe apparatus recited in any of the claims.

BRIEF DESCRIPTION OF DRAWINGS

Exemplary embodiments of the invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 schematically illustrates a mobile telecommunication system of atype to which the invention is applicable;

FIG. 2 schematically illustrates the relationship between some of theentities forming part of the mobile telecommunication system of FIG. 1;

FIG. 3 schematically illustrates various radio transceiver circuitsimplemented on a mobile device of the mobile telecommunication systemshown in FIG. 1;

FIG. 4 schematically illustrates various radio transceiver circuitsimplemented on the base station of the mobile telecommunication systemshown in FIG. 1;

FIG. 5 is a block diagram of a mobile device forming part of the mobiletelecommunication system shown in FIG. 1;

FIG. 6 is a block diagram of the home base station forming part of themobile telecommunication system shown in FIG. 1;

FIG. 7 is a block diagram of the access point forming part of the mobiletelecommunication system shown in FIG. 1;

FIGS. 8a to 11 are exemplary timing diagrams illustrating variousmethods performed by the nodes forming part of the mobiletelecommunication system shown in FIG. 1; and

FIG. 12 illustrates some of the frequency bands and channels that may beaffected by interference arising from the coexistence of LTE and non-LTEtechnologies in the same base station.

DESCRIPTION OF EMBODIMENTS

Overview

FIG. 1 schematically illustrates a mobile (cellular) telecommunicationsystem 1 in which users of mobile devices 3 (for example mobiletelephones 3-1 to 3-3) can communicate with other users via one or morebase stations 5 and a core network 7. In the system illustrated in FIG.1, the base station 5 is a dual mode base station (dual FAP) whichcomprises an LTE home base station (HeNB) part 5-1 (e.g. a pico/femtobase station or other low-power node) and a non-LTE access point (AP)part 5-2 (e.g. a Wi-Fi AP). In this example, the HeNB part 5-1 and theAP part 5-2 are co-located (and hence they share at least some hardwareand/or software components), although the HeNB part 5-1 and the AP part5-2 may also be implemented as two physically separate units. Anappropriate dedicated interface (e.g. an internal interface or anexternal one) is provided for communications between the HeNB part 5-1and the AP part 5-2. Further details about the relationship (andcommunication links provided) between the HeNB part 5-1 and the AP part5-2 and various associated network nodes are illustrated in FIG. 2.

Both the HeNB part 5-1 and the AP part 5-2 operate at least one cell(not shown), each cell having a number of uplink (UL) and downlink (DL)communication resources (channels, sub-carriers, time slots, etc.) thatare available for wireless communications between the mobile devices 3and the dual FAP 5 (i.e. the HeNB part 5-1 and/or the AP part 5-2). Inthis example, the Radio Access Technologies (RATs) employed by the dualFAP 5 operate according to either Frequency Division Duplexing (FDD) orTime Division Duplexing (TDD). In TDD, the time domain of acommunication channel is divided into several recurrent time slots offixed length in which communication to/from the dual FAP 5 can bescheduled. In operation in TDD, two or more data streams may betransferred between the dual FAP 5 (e.g. HeNB part 5-1) and the mobiledevice(s) 3, apparently simultaneously, in sub-channels of onecommunication channel, by scheduling each data stream in different timeslots of the channel (effectively ‘taking turns’). In FDD, the bandwidthavailable to the base station is divided into a series ofnon-overlapping frequency sub-bands each comprising frequency resourcesthat may be assigned to mobile device(s) 3 for communication via thedual FAP 5.

In this example, the first mobile device 3-1 is connected to both theHeNB part 5-1 and the AP part 5-2, whilst the second mobile device 3-2is connected to the HeNB part 5-1 only, and the third mobile device 3-3is connected to the AP part 5-2 only. Whilst this particular arrangementis shown in FIG. 1 for purely illustrative purposes, it will beappreciated that compatible mobile devices 3 may connect to either oneor both of the HeNB part 5-1 and the AP part 5-2 (and/or to any furtherbase station) depending on their capabilities, applicableconfigurations, and/or network conditions that are outside the scope ofthe present invention.

As can be seen, at least the mobile devices 3-1 and 3-3 are capable ofcommunicating using non-LTE radio technologies such as those which useresources of the Industrial, Scientific and Medical (ISM) frequencybands. In this example, the mobile devices 3-1 and 3-3 can communicatewith the AP part 5-2 of the dial FAP 5 operating according to one of the802.11 family of standards (Wi-Fi) defined by the Institute ofElectrical and Electronics Engineers (IEEE). Although not shown in FIG.1, each of the mobile devices 3 may also be able to communicate withother non-LTE transceivers, e.g. with a wireless headset operatingaccording to the Bluetooth standard defined by the Bluetooth SpecialInterest Group (SIG) and/or support positioning technologies and thuscommunicate with, for example, a positioning satellite using GPSsignals.

Communications between the mobile device(s) 3 and the AP part 5-2 (andpossibly between the mobile devices 3 and other non-LTE transceivers)might occur substantially concurrently with the communications betweenthe mobile device(s) 3 and the HeNB part 5-1, which concurrentcommunications have the potential to cause undesirable interference(i.e. IDC interference).

The issue of IDC interference is illustrated further in FIG. 3 whichschematically illustrates, purely illustratively, the various radiotransceiver circuits implemented on a mobile device 3 shown in FIG. 1.Further, FIG. 4 schematically illustrates, purely illustratively, thevarious radio transceiver circuits implemented on the dual FAP 5 shownin FIG. 1. As shown in FIG. 3, the mobile device (e.g. mobile device3-1) comprises an LTE baseband circuit 30 a, a GPS baseband circuit 30b, and an ISM baseband circuit 30 c. Each baseband circuit 30 a to 30 cis coupled to a radio frequency (RF) transceiver (or receiver), i.e. LTERF transceiver 31 a, GPS RF transceiver 31 b, and ISM RF transceiver 31c, respectively. Communications in the LTE band are carried out using anLTE antenna 33 a. Similarly, communications in the non-LTE bands arecarried out using the respective GPS antenna 33 b and/or the ISM antenna33 c.

As indicated by dashed arrows in FIG. 3, any of the transceivers 31 a to31 c might suffer interference from either one of the other transceiversoperating in the same mobile device 3. Similarly, as indicated by dashedarrow in FIG. 4, the transceivers 51-1 and 51-2 of the base station 5might also suffer interference from each other (and/or from thetransceivers 31 a to 31 c of the mobile device 3).

Returning to FIG. 1, the dual FAP 5 is beneficially configured toalleviate any such in-device coexistence (IDC) interference.Specifically, the HeNB part 5-1 and the AP part 5-2 are configured toco-ordinate their operations, e.g. by exchanging information using thededicated interface 100 provided therebetween (e.g. an interfaceprovided directly between the HeNB part 5-1 and the AP part 5-2 and/orusing an external connection, such as a connection provided via one ormore gateways and/or the core network 7).

In particular, the HeNB part 5-1 and the AP part 5-2 are configured tointeract with each other for the alleviation of an (ongoing/potential)IDC interference by exchanging information relating to one or more ofthe following functionalities:

-   -   interference management;    -   power control;    -   carrier frequency re-selection;    -   energy saving;    -   radio transmission state (e.g. on/off); and    -   load balancing.

For example, by exchanging some of the above information, the dual FAP 5is beneficially able to alleviate an IDC interference in LTE Band 40(which may be caused by transmissions, in the lower portion of the ISMband, to LTE Band 40, or vice versa). In this case, one or more of thefollowing solutions may be applied by the dual FAP 5:

-   -   i) the HeNB part 5-1 may request the AP part 5-2 not to use one        or more channels close to the lower portion of the ISM band        (e.g. ISM Channels 1 to 3), i.e. to select other channels if        possible;    -   ii) the HeNB part 5-1 may restrict (avoid) scheduling the PRBs        in the higher portion of LTE Band 40 in both uplink and downlink        (i.e. in a region close to ISM Channel 1) when the coexisting        Wi-Fi devices, such as the AP part 5-2 and a Wi-Fi capable        mobile device 3, use one or more ISM channels close to LTE Band        40; and    -   iii) the HeNB part 5-1 may impose power restrictions (for LTE        communications) while scheduling the PRBs in the higher portion        of LTE Band 40 in both uplink and downlink (i.e. in a region        close to ISM Channel 1) if it is found necessary to use these        PRBs (e.g. if solution ii) is not or cannot be employed).

Similarly to the above, the dual FAP 5 is also beneficially able toalleviate an IDC interference in LTE Band 7 (which may be caused bytransmissions, in ISM Channel 14, to LTE Band 7, or vice versa, sincethere is only a 5 MHz separation between the uplink portion of LTE Band7 and Wi-Fi Channel 14, and almost half of Wi-Fi Channel 14 lies withinthe LTE guard band). In this case, one or more of the following possiblesolutions may be applied by the dual FAP 5:

-   -   iv) the HeNB part 5-1 may request the AP part 5-2 not to use one        or more channels close to the higher portion of the ISM band        (e.g. ISM Channels 12 to 14), i.e. to select other channels if        possible;    -   v) the HeNB part 5-1 may restrict (avoid) scheduling the PRBs in        the lower portion of LTE Band 7 in uplink (i.e. in a region        close to ISM Channel 14) when the coexisting Wi-Fi devices (such        as the AP part 5-2 and a Wi-Fi capable mobile device 3) are        using one or more channels close to LTE Band 7; and    -   vi) the HeNB part 5-1 may obtain timing information from the AP        part 5-2, using which information the HeNB part 5-1 may be        arranged to avoid scheduling any uplink (LTE) communications (at        least in LTE Band 7) at least for the duration of any ISM        transmission by the AP part 5-2 (or the mobile devices 3) in        Wi-Fi Channel 14.    -   It will be appreciated that solutions iv) to vi) may also be        applied to LTE Band 41 instead of (or in addition to) LTE Band        7.

Furthermore, the HeNB part 5-1 may be configured to adjust its maximumtransmission power on the downlink (and/or to adjust the maximumtransmission power allowed for the mobile device 3 on the uplink) inaccordance with information relating to the operation of the AP part 5-2(e.g. channels used, transmit powers, etc.), and thereby alleviate anyinterference caused by the LTE transmissions of the HeNB part 5-1 to theAP part 5-2. Similarly, the AP part 5-2 may be advantageously configuredto obtain information from the HeNB part 5-1 relating to the currentlyused/permitted power (e.g. maximum or average power) by the HeNB part5-1 for its downlink and uplink communications with the mobile devices3, and to adjust its own transmissions accordingly.

The HeNB part 5-1 may also be configured to alleviate any interferencecaused by the LTE transmissions of the HeNB part 5-1 to the AP part 5-2by initiating carrier frequency re-selection procedures with respect tothe mobile devices 3 for which LTE communications are scheduled in LTEBands prone to causing interference to (or experiencing interferencefrom) the ISM communications. For example, the HeNB part 5-1 may beconfigured to determine, based on information relating to the operationof the AP part 5-2 (e.g. the ISM channels and/or the associatedtransmission power being used), which carrier frequency needs to bere-selected (e.g. instead of an interfering or potentially interferingcarrier frequency currently used).

Moreover, the HeNB part 5-1 and the AP part 5-2 may also be configuredto inform each other when their transceivers are entering and/or exitinga low-power operating mode (e.g. an energy saving mode) during whichtransmissions over one or more (e.g. all) frequency bands are suspended.Using the exchanged information relating to the current power state ofthe HeNB part 5-1 and/or the AP part 5-2, the dual FAP 5 is beneficiallyable to alleviate a potential interference by restricting/allowing theuse of certain frequency bands/channels in dependence on the currentoperating mode of the HeNB part 5-1 and/or the AP part 5-2. For example,the AP part 5-2 may restrict usage of certain ISM channels whilst theHeNB part 5-1 is operating at normal power (i.e. whilst the HeNB part isnot in a power saving mode) and allow usage of such ISM channels whilstthe HeNB part 5-1 is operating in a power saving mode (and this has beeninformed by the HeNB part 5-1).

The HeNB part 5-1 and the AP part 5-2 may also be configured to performload balancing (e.g. by steering traffic between the HeNB part 5-1 andthe AP part 5-2) based on the information exchanged between them. Inthis case, the exchanged information may relate to the number of mobiledevices 3 served by the HeNB part 5-1 and the AP part 5-2, respectivelyand/or the associated load (or remaining capacity) thereof.

In summary, any of the above approaches may beneficially contribute tothe alleviation (e.g. reduction, prevention) of interference arising dueto the co-location of the HeNB part 5-1 and the AP part 5-2 in the dualFAP 5 (and/or the like). This in turn may increase the overall datathroughput that can be achieved by the dual FAP 5 compared to other dualmode base stations that do not support the above features.

Mobile Device

FIG. 5 is a block diagram of a mobile device 3 forming part of themobile telecommunication system 1 shown in FIG. 1. As shown, the mobiledevice 3 includes transceiver circuits 31 a to 31 c which are operableto transmit signals to and to receive signals from the base station 5via one or more antennas 33 a to 33 c. Although not necessarily shown inFIG. 5, the mobile device 3 may of course have all the usualfunctionality of a conventional mobile telephone (such as a userinterface 35) and this may be provided by any one or any combination ofhardware, software and firmware, as appropriate. The mobile device 3 hasa controller 37 to control the operation of the mobile device 3. Thecontroller 37 is associated with a memory 39 and is coupled to thetransceiver circuits 31 a to 31 c. The controller 37 controls theoperation of the transceiver circuits 31 a to 31 c in accordance withsoftware and data stored in memory 39.

Software may be pre-installed in the memory 39 and/or may be downloadedvia the telecommunications network or from a removable data storagedevice (RMD), for example. The software includes, among other things, anoperating system 41, an LTE module 43, an ISM module 45, a GPS module 47(optional), a measurement and reporting module 48, and a trafficsteering module 49.

The LTE module 43 controls the communications of the mobile device 3using the LTE radio technologies. The LTE module 43 receivesinstructions from the base station 5 (via the LTE transceiver circuit 31a and the LTE antenna 33 a) and stores them in the memory 39. Based onthe received instructions, the LTE module 43 is operable to select theappropriate frequency band, transmission power, modulation mode etc.used in the LTE communications. The LTE module 43 is also operable toupdate the base station 5 about the amount and type of uplink and/ordownlink data scheduled for transmission in order to assist the basestation 5 in allocating resources among the mobile devices it isserving.

The ISM module 45 controls the ISM (e.g. IEEE 802.11) communications ofthe mobile device 3. In doing so, the ISM module 45 might, for example,use data received from the access point part 5-2 and/or communicate witha wireless headset and/or the like.

If present, the GPS module 47 is operable to obtain a current geographiclocation of the mobile device 3 and to control the GPS communications ofthe mobile device 3. In doing so, the GPS module 47 might, for example,use data received from a positioning satellite.

The measurement and reporting module 48 is responsible for performingsignal measurements (including interference measurements) and togenerate and send (via the LTE transceiver 31 a) a measurement report tothe HeNB part 5-1. In order to do so, the measurement and reportingmodule 48 is operable to obtain a measurement configuration from theHeNB part 5-1. The measurement and reporting module 48 may also beoperable to indicate the occurrence of in-device interference by sendingan associated IDC indication to the HeNB part 5-1 via the LTEtransceiver 31 a. In this embodiment the measurement and reportingmodule 48 and the HeNB part 5-1 communicates using one or more dedicatedradio resource control (RRC) message although any appropriate signallingmay be used.

The traffic steering module 49 is responsible for steering trafficbetween the HeNB part 5-1 and the AP part 5-2, as instructed by the dualFAP 5. In order to do so, the traffic steering module 49 is operable toreceive and process a steering command from the HeNB part 5-1. Suchsteering command may be received, for example, subsequent to (e.g. inresponse to) the measurement and reporting module 48 sending ameasurement report to the HeNB part 5-1.

LTE Base Station

FIG. 6 is a block diagram of the HeNB part 5-1 of the dual FAP 5 formingpart of the mobile telecommunication system 1 shown in FIG. 1. As shown,the HeNB part 5-1 includes a transceiver circuit 51-1 which is operableto transmit signals to and to receive signals from the mobile devices 3via one or more antennas 53-1 and to transmit signals to and receivesignals from the core network 7 and other base stations via the networkinterface 55 (which may be a copper or optical fibre interface). Acontroller 57 controls the operation of the transceiver circuit 51-1 inaccordance with software and data stored in memory 59. The softwareincludes, among other things, an operating system 61, an LTEcommunication control module 63, a radio resource control (RRC) module65, and an ISM interface module 67 (which includes a load balancingmodule 70, a channel control module 71, and a power control module 72).

The communication control module 63 controls communications between theHeNB part 5-1 (i.e. the LTE base station part of the dual FAP 5) andexternal devices (such as the mobile devices 3) via the transceivercircuit 51-1 and the one or more antenna 53-1. The communication controlmodule 63 also controls communications between the HeNB part 5-1 andcore network nodes (such as the MME 12, the S-GW 14, and/or the P-GW 16)via the transceiver circuit 51-1 and the network interface 55 (which maycomprise e.g. an S1 interface).

The RRC module 65 manages (generates, sends, and receives) messagesformatted in accordance with the RRC protocol. For example, the RRCmodule 65 is operable to communicate RRC messages with the mobiledevices 3 (e.g. RRC messages relating to signal measurements).

The ISM interface module 67 controls communication with the AP part 5-2(with the corresponding LTE interface module 69 thereof) over thededicated interface 100 provided between the HeNB part 5-1 and the APpart 5-2. For example, the ISM interface module 67 is operable toexchange information with the AP part 5-2 in order to assist thealleviation of interference resulting from the simultaneous use of boththe LTE and the non-LTE (ISM) communication technologies. Specifically,the ISM interface module 67 includes the load balancing module 70, whichis responsible for performing load balancing based in informationexchanged with the AP part 5-2. The ISM interface module 67 alsoincludes the channel control module 71, which is responsible forperforming channel control based in information exchanged with the APpart 5-2. In this example, the ISM interface module 67 further includesthe power control module 72, which is responsible for performing powercontrol (based in information exchanged with the AP part 5-2). It willbe appreciated that the ISM interface module 67 may include a number ofadditional modules and/or that any of the modules 70 to 72 (and/or anysuch additional modules) may be combined, if appropriate.

Access Point

FIG. 7 is a block diagram of the access point part 5-2 of the dual FAP 5forming part of the mobile telecommunication system 1 shown in FIG. 1.As shown, the access point part 5-2 includes a transceiver circuit 51-2which is operable to transmit signals to and to receive signals from themobile devices 3 via one or more antennas 53-2 and to transmit signalsto and receive signals from the core network 7 and other base stations 5via the network interface 55 (which may be a copper or optical fibreinterface). A controller 57 controls the operation of the transceivercircuit 51-2 in accordance with software and data stored in memory 59.The software includes, among other things, an operating system 61, anon-LTE (e.g. ISM) communication control module 64, and an LTE interfacemodule 69 (which includes a load balancing module 70, a channel controlmodule 71, and a power control module 72)

The communication control module 64 controls communications between theaccess point part 5-2 and external devices (such as the mobile devices3) via the transceiver circuit 51-2 and the one or more antenna 53-2.The communication control module 64 also controls communications betweenthe AP part 5-2 and other network nodes (either directly or via one ormore gateways) via the transceiver circuit 51-2 and the networkinterface 55.

The LTE interface module 69 controls communication with the HeNB part5-1 (with the corresponding ISM interface module 67 thereof) over thededicated interface 100 provided between the HeNB part 5-1 and the APpart 5-2. For example, the LTE interface module 69 is operable toexchange information with the HeNB part 5-1 in order to assist thealleviation of interference resulting from the simultaneous use of boththe LTE and the non-LTE (ISM) communication technologies. Specifically,the LTE interface module 69 includes the load balancing module 70, whichis responsible for performing load balancing based in informationexchanged with the HeNB part 5-1. The LTE interface module 69 alsoincludes the channel control module 71, which is responsible forperforming channel control based in information exchanged with the HeNBpart 5-1. In this example, the LTE interface module 69 further includesthe power control module 72, which is responsible for performing powercontrol (based in information exchanged with the HeNB part 5-1). It willbe appreciated that the LTE interface module 69 may include a number ofadditional modules and/or that any of the modules 70 to 72 (and/or anysuch additional modules) may be combined, if appropriate.

In the above description, the mobile device 3, the home base station5-1, and the access point part 5-2 are described for ease ofunderstanding as having a number of discrete modules (such as thecommunication control modules and the LTE/ISM interface modules). Whilstthese modules may be provided in this way for certain applications, forexample where an existing system has been modified to implement theinvention, in other applications, for example in systems designed withthe inventive features in mind from the outset, these modules may bebuilt into the overall operating system or code and so these modules maynot be discernible as discrete entities.

Operation

Examples of methods used for alleviating interference, between the homebase station 5-1 and the access point part 5-2 of a dual FAP 5, will nowbe described. Although for efficiency of understanding for those skilledin the art, the invention will be described in detail in the context ofa home base station (HeNB part) and an access point part of a dual FAP,the principles described herein can be applied to a ‘multimode’ FAPcomprising more than one (home) base station and/or more than one accesspoint part (which may each operate according to different standards)with the corresponding elements of the system changed as required.

First Embodiment

FIG. 8a shows an exemplary timing diagram illustrating a methodperformed by the HeNB part 5-1 and the AP part 5-2 of the mobiletelecommunication system 1 shown in FIG. 1. In this example, the HeNBpart 5-1 and the AP part 5-2 are configured to apply channelrestriction, e.g. in order to alleviate (on-going or potential)interference resulting from the simultaneous use of both the LTE and thenon-LTE (ISM) communication technologies.

As mentioned above, the HeNB part 5-1 and the AP part 5-2 are configuredto alleviate any IDC interference (ongoing and/or potential) byexchanging information (either within the dual FAP 5 or using anexternal connection, such as a connection provided via one or moregateways and/or the core network 7).

In this example, the HeNB part 5-1 requests the AP part 5-2 not to useone or more channels close to the lower portion of the ISM band (e.g.ISM Channels 1 to 3). In order to do so, the HeNB part 5-1 generates(using its ISM interface module 67/channel control module 71) and sends,in step S801, an appropriately formatted message (e.g. a ‘RestrictChannel Request’ message) to the AP part 5-2, requesting the AP part 5-2to apply channel restriction with respect to one or more ISM channels.The HeNB part 5-1 also includes in the message sent at S801 informationidentifying the channels to be restricted (e.g. a channel ID associatedwith the ISM channel and/or a band ID associated with the interferingLTE band).

In response to the HeNB's 5-1 request, the AP part 5-2 determines (usingits channel control module 71) whether or not it is able to apply therequested restriction. If the AP part 5-2 determines that it is able toproceed with the HeNB's 5-1 request, it begins to apply (in step S803)the channel restriction (using its channel control module 71) withrespect to the ISM channel(s) identified in the request received atS801. Such a channel restriction may be maintained by the AP part 5-2 atleast until receiving a further message from the HeNB part 5-1 liftingthe restriction and/or until the expiry of an associated ‘channelrestriction’ timer (which may be set to e.g. a default timer valueand/or a timer value configured by the message at S801).

Once the AP part 5-2 has complied with the requested channelrestriction, it generates (using its LTE interface module 69) and sends,in step S805 a, an appropriate signalling message (e.g. a ‘RestrictChannel Acknowledgement’ message) informing the HeNB part 5-1 that therestriction is in place. Advantageously, the HeNB part 5-1 is able tocommunicate with the mobile devices 3 using the LTE channelsneighbouring or overlapping with the ISM channel(s) operated by the APpart 5-2 without causing unnecessary interference to thesecommunications.

It will be appreciated that any communications already allocated to therestricted ISM channel(s) may be either terminated or moved (handedover, steered, etc.) to a different (i.e. non-restricted) channel.

In this embodiment, the HeNB part 5-1 may use, for example, LTEfrequency Band 40 and it may request the AP part 5-2 to restrict usageof at least one of ISM Channels 1 to 3. The HeNB part 5-1 may also useLTE frequency Band 7 (and/or LTE Band 41), in which case it may requestthe AP part 5-2 to restrict usage of at least one of ISM Channels 12 to14.

Second Embodiment

FIG. 8b shows a modification of the method shown in FIG. 8a . In thiscase, the AP part 5-2 is unable to comply with the requested channelrestriction and the HeNB part 5-1 is configured to alleviateinterference on its own.

Step S801 of FIG. 8b is identical to step S801 of FIG. 8a . However, inthis case the AP part 5-2 (using its channel control module 71)determines that the requested channel restriction cannot be applied.This may happen, for example, when such restriction is already in place,the channel to be restricted is not supported by the AP part 5-2, thechannel is used by communications that cannot be interrupted/moved toother channels, and/or the like.

As shown generally in step S803, the AP part 5-2 does not apply therequested channel restriction. Instead, the AP part 5-2 generates (usingits LTE interface module 69) and sends, in step S805 b, an appropriatesignalling message (e.g. a ‘Restrict Channel Negative Acknowledgement(Nack)’ message) informing the HeNB part 5-1 that the requestedrestriction cannot be complied with (at least with respect to some ofthe channel identified in the message at S801).

Advantageously, in this case the HeNB part 5-1 is able to apply ascheduling restriction (using its channel control module 71) and/orapply power control (using its power control module 72) to its owncommunications (e.g. with the mobile device 3-1) over the affected LTEBand. Thus, for example, if the AP part 5-2 is unable to restrict usageof at least one of ISM Channels 1 to 3, the HeNB part 5-1 may restrictusage of its own LTE frequency Band 40 (in downlink, uplink, or both).If the AP part 5-2 is unable to restrict usage of at least one of ISMChannels 12 to 14, the HeNB part 5-1 may restrict usage of its own LTEfrequency Band 7 (and/or Band 41), in downlink and/or uplink.

The HeNB part 5-1 is thus able to communicate with the mobile devices 3without causing unnecessary interference to these communications usingappropriate LTE bands (i.e. non-restricted bands) even if the AP part5-2 cannot or does not comply with the requested restriction.

Third Embodiment

FIG. 9a shows another modification of the method shown in FIG. 8a .Similarly to FIG. 8b , in this case the AP part 5-2 is unable to complywith the requested channel restriction and the HeNB part 5-1 isconfigured to alleviate interference on its own.

Steps S901 to S905 a correspond to steps S801 to S805 b of FIG. 8b ,respectively, hence their description will not be repeated here.

In this case however, as shown in step S907, the HeNB part 5-1 (usingits channel control module 71) applies a scheduling restriction and/orintelligent uplink scheduling to its own communications (e.g. with themobile device 3-1) over the affected LTE Band(s). This may beparticularly beneficial in case of LTE Band 7 in the uplink in case theAP part 5-2 is unable to restrict usage of at least one of ISM Channels12 to 14. However, it will be appreciated that this modification mayalso be applied to downlink communications in LTE Band 7 and/orcommunications in other bands, e.g. LTE Bands 40/41, as described above.

Additionally, the HeNB part 5-1 may also be configured to obtain fromthe AP part 5-2 (e.g. in step S905 a or in a separate step) informationidentifying a frame timing applied by the AP part 5-2, i.e. informationidentifying the transmission pattern (if any) and/or duration used bythe AP part 5-2 over the interfering channel. Beneficially, the HeNBpart 5-1 is able to apply intelligent uplink scheduling for the affectedLTE Band(s) using the obtained frame timing information, e.g. byavoiding scheduling UL transmissions in the affected LTE band(s) (e.g.Band 7/41) for the duration of the AP's 5-2 transmissions in theinterfering ISM Channel(s) (e.g. Channel 12/13/14).

Fourth Embodiment

FIG. 9b shows an exemplary timing diagram illustrating a methodperformed by the HeNB part 5-1 and the AP part 5-2 of the mobiletelecommunication system 1 shown in FIG. 1. In this example, the HeNBpart 5-1 is configured to control its maximum transmit power based oninformation obtained from the AP part 5-2.

Initially, as generally shown in step S910, the HeNB part 5-1 receivesthe applicable maximum transmission (‘Tx’) power value from the HomeeNodeB Management System (HeMS). The HeNB part 5-1 is configured toadjust, based on information obtained from the AP part 5-2, its maximumtransmission power, thereby reducing (as much as possible) the amount ofinterference to the coexisting AP part 5-2.

Specifically, in this example the AP part 5-2 (using its power controlmodule 72) generates and sends, in step S911, an appropriately formattedmessage (e.g. a ‘Channel/Transmit Power Information Request’ message) tothe HeNB part 5-1, e.g. over the dedicated interface 100. The AP part5-2 includes in this message information identifying one or more channel(e.g. at least one of ISM Channels 1 to 3, and 12 to 14) used by the APpart 5-2 in its communications with the mobile devices 3, and arespective associated transmit power used in the identified one or morechannel.

Next, in step S913, the HeNB part 5-1 configures its power controlmodule 72 to apply an appropriate UL/DL maximum transmit power, whichalso takes into account the received information identifying the one ormore channel used by the AP part 5-2 and the respective associatedtransmit power.

Specifically, the HeNB part 5-1 is configured to adjust the value of theso-called ‘Pmax’ parameter (which determines the HeNB's 5-1 maximumtransmission power) based on an offset that is dependent on the channelinformation and/or power used by AP part 5-2. Further, the HeNB part 5-1is configured to adjust/set the maximum allowed UL transmit power of themobile devices 3 within the cell operated by the HeNB part 5-1, alsobased on the received information identifying the one or more channelused by the AP part 5-2 and the respective associated transmit power. Itwill be appreciated that in determining an appropriate UL/DL maximumtransmit power the HeNB part 5-1 may be configured to take into accountother information as well, for example, information relating to networkmonitor mode (NMM) measurements (also referred to as Network Listen Mode(NLM) measurements).

Once the HeNB part 5-1 has successfully configured its power controlmodule 72 with the appropriate UL/DL maximum transmit powers, itgenerates (using its ISM interface module 67) and sends, in step S915,an appropriate signalling message (e.g. a ‘Channel/Transmit PowerInformation Acknowledgement’ message) to the AP part 5-2.

Beneficially, by applying an appropriate transmit power setting (to theHeNB's 5-1 transmissions) that also take into account the informationidentifying the AP's 5-2 channel(s) and associated transmit power(s),the HeNB part 5-1 is able to alleviate (on-going or potential)interference resulting from the simultaneous use of both the LTE and thenon-LTE (ISM) communication technologies in the dual FAP 5.

Fifth Embodiment

FIGS. 10a and 10b show exemplary timing diagrams illustrating a methodperformed by the HeNB part 5-1 and the AP part 5-2 of the mobiletelecommunication system 1 shown in FIG. 1. In this example, the HeNBpart 5-1 is configured to control the AP's 5-2 band restriction based onthe current operating state of the HeNB part 5-1.

The procedure begins in step S1000, in which the HeNB part 5-1 enters anenergy saving mode (ESM), e.g. during which transmissions over one ormore (e.g. all) LTE frequency bands are suspended. In response to thischange of operating mode, the HeNB part 5-1 (using its ISM interfacemodule 67) generates and sends, in step S1001, an appropriatelyformatted message (over the dedicated interface 100) informing the APpart 5-2 about the activation of the energy saving mode. The HeNB part5-1 may also include in this message information identifying the LTEBands in which its transmissions are suspended (e.g. if not all LTEBands are suspended) and/or for which the ESM is applicable.

In response to this message, as shown in step S1003, the AP part 5-2(using its channel control module 71 and/or power control module 72)discontinues the enforcement of any restriction that has been applied toits ISM transmissions (e.g. in any of Channels 1 to 3, and 12 to 14).The AP part 5-2 (using its LTE interface module 69) generates and sends,in step S1005, an appropriately formatted message (e.g. an ‘Entering ESMResponse’ message) to the HeNB confirming that the ISM band restrictionshave been lifted.

FIG. 10b illustrates the reverse of this procedure, in which the HeNBpart 5-1 exits the energy saving mode of operation and notifies the APpart 5-2 to start applying one or more restrictions to its ISMcommunications thereby alleviating a potential interference arising dueto the concurrent use the LTE and non-LTE technologies.

As shown in step S1010, this procedure begins when the HeNB part 5-1exits the energy saving mode of operation (e.g. the ESM mode describedabove). In response to this change of operating mode, the HeNB part 5-1(using its ISM interface module 67) generates and sends, in step S1011,an appropriately formatted message (e.g. over the dedicated interface100) informing the AP part 5-2 about the HeNB part 5-1 resuming itsnormal (i.e. non-ESM) mode of operation, in which the HeNB's 5-1transmissions over the LTE frequency bands are no longer suspended (e.g.the de-activation of the energy saving mode entered in step S1010). TheHeNB part 5-1 may also include in this message information identifyingthe LTE Bands in which its transmissions are no longer suspended and/orLTE Bands in which its transmissions are suspended (e.g. if some LTEBands remain suspended).

In response to this message, as shown in step S1013, the AP part 5-2(using its channel control module 71 and/or power control module 72)begins applying an enforcement of the restriction to its ISMtransmissions (e.g. in any of Channels 1 to 3, and 12 to 14). It will beappreciated that the required restrictions may be identified by the HeNBpart 5-1 including appropriate information in the message sent at S1011and/or in any other suitable message (such as the messages describedabove with reference to FIGS. 8a to 9b ).

Next, the AP part 5-2 (using its LTE interface module 69) generates andsends, in step S1015, an appropriately formatted message (e.g. an‘Exiting ESM Response’ message) to the HeNB confirming that the ISM bandrestrictions have been (re-) applied.

It will be appreciated that at this point the procedure may return tostep S1010, e.g. if the HeNB part 5-1 subsequently enters its energysaving mode.

Thus, in summary, whenever the HeNB part 5-1 enters the energy savingmode, it may inform the AP part 5-2 (e.g. over the dedicated interface100) about its current energy saving mode (and/or its mode transition)so that the AP part 5-2 can beneficially lift any restriction (e.g. arestriction on ISM channel usage, transmission power, and/or scheduling)that have been imposed by the HeNB part 5-1 in order to alleviate aninterference arising due to the coexistence of the LTE and non-LTEtransmissions. Similarly, whenever the HeNB part 5-1 exits the energysaving mode, it may inform the AP part 5-2 about its current energysaving mode (and/or its mode transition) so that the AP part 5-2 canbeneficially apply (or re-apply, as appropriate) any requestedrestriction (e.g. a restriction on ISM channel usage, ISM transmissionpower, and/or ISM scheduling) in order to alleviate an interference (orpotential interference) arising from the coexistence of the LTE andnon-LTE technologies in the dual FAP 5.

It will be appreciated that, by effectively mirroring the abovedescribed procedures, the AP part 5-2 may also be configured to informthe HeNB part 5-1 about its current energy saving mode (and/or energysaving mode transition), in which case the HeNB part 5-1 may apply/liftan appropriate restriction to its own transmissions in an LTE Bandaffected by the AP's 5-2 ISM transmissions, in dependence on the AP's5-2 actual energy saving mode.

The state transitions and the associated notifications sent between theHeNB part 5-1 and the AP part 5-2 (in either direction) are furtherillustrated in FIG. 10 c.

Using the exchanged information relating to the current power state ofthe HeNB part 5-1 and/or the AP part 5-2, the dual FAP 5 is beneficiallyable to alleviate a potential interference by restricting/allowing theuse of certain frequency bands/channels in dependence on the currentoperating mode of the HeNB part 5-1 and/or the AP part 5-2.

Sixth Embodiment

FIG. 11 shows an exemplary timing diagram illustrating a methodperformed by the HeNB part 5-1 and the AP part 5-2 of the mobiletelecommunication system 1 shown in FIG. 1. In this example, the HeNBpart 5-1 is configured to control the steering of traffic to/from the APpart 5-2 based on load information obtained from the AP part 5-2.

It will be appreciated that in this embodiment the messages used betweenthe HeNB part 5-1 and the mobile device 3 (denoted ‘UE’ in FIG. 11)conform to the RRC protocol specified in 3GPP TS 36.331. Specifically,the message sent at S1101 may comprise an ‘RRCConnectionReconfigurationmessage’ described in Section 5.5.1 of TS 36.331 and the message sent atS1104 corresponds to the message described in Section 5.5.5 “Measurementreporting” of TS 36.331. Step S1102 may correspond to any of the eventtriggers A1 to A6, B1, and B2 described in sections 5.5.4.2 to 5.5.4.8of TS 36.331. The contents of the above sections of TS 36.331 areincorporated herein by reference. Further, step S1102 may comprise anevent trigger relating to a non-LTE (e.g. ISM) measurement, such as aWi-Fi signal strength measurement, a Wi-Fi interference measurement,and/or the like.

In this case however, as generally illustrated in step S1100, the HeNBpart 5-1 is operable to obtain load information (e.g. congestion statusinformation) from the AP part 5-2. It will be appreciated that althoughin FIG. 11 step S1100 is shown to take place between steps S1104 andS1105, step S1100 may take place any time before step S1105, e.g. priorto or after S1101. Further, it will be appreciated that the message atstep S1100 may be sent by the AP part 5-2 in response to an associatedrequest (not shown in FIG. 11) received from the HeNB part 5-1 (e.g.over the dedicated interface 100).

In any case, the HeNB part 5-1 is configured to take into account theload information obtained from the Wi-Fi AP part 5-2 (e.g. instead or inaddition to the measurement report received at S1104) in its decision totrigger the steering of traffic to/from the Wi-Fi AP part 5-2. Thus,when the HeNB part (using its load balancing module 70) determines thatsome or all mobile devices 3 may be steered to/from the Wi-Fi AP part5-2, it generates (using e.g. its RRC module 65) and sends, in stepS1105, an appropriately formatted signalling message requesting themobile devices 3 to steer to/from the Wi-Fi AP part 5-2 in dependence onthe load (e.g. congestion status/capacity) of the AP 5-2 part indicatedby the load information received at S1100, thereby alleviating the(potential) interference arising from the coexistence of the LTE andnon-LTE technology in the dual FAP 5.

For example, if the load information from the AP part 5-2 indicates thatthe load of the AP part 5-2 (e.g. the number of mobile devices served inthe AP's 5-2 cell and/or the amount of its capacity used) is above apredetermined threshold, then the HeNB part 5-1 instructs the mobiledevice 3 to steer away from the AP part 5-2 (and to possibly use anotherAP part and/or to use the LTE technology instead). However, if the loadinformation from the AP part 5-2 indicates that the load of the AP part5-2 is not above (e.g. it is below) a predetermined threshold, then theHeNB part 5-1 instructs the mobile device 3 to steer to the AP part 5-2and/or another access point part (e.g. from the HeNB part 5-1).

As shown generally in step S1107, the mobile device 3 complies with theHeNB's 5-1 steering command, and performs an appropriate steering of itscommunications to/from the wireless local area network (WLAN) that theAP part 5-2 belongs to. Finally, the mobile device 3acknowledges/confirms successful receipt of the steering command.

In either scenario, by steering the mobile device 3 to/from the AP part5-2/WLAN, the dual FAP 5 is beneficially able to alleviate an undesiredinterference arising from its concurrent use (the coexistence) of theLTE and non-LTE technology.

Modifications and Alternatives

A detailed exemplary embodiment has been described above. As thoseskilled in the art will appreciate, a number of modifications andalternatives can be made to the above embodiment whilst still benefitingfrom the inventions embodied therein.

Although the mechanism described here is for co-located dual mode FAPs,it can also be extended to the FAP devices that are not co located bute.g. in close proximity. It will be appreciated that in this case themessages may be exchanged, for example, through a common gateway and/ora controlling node.

In the above exemplary embodiment, a mobile telephone basedtelecommunication system was described. As those skilled in the art willappreciate, the techniques described in the present application can beemployed in other communication systems. Other communication nodes ordevices (both mobile and stationary) may include user devices such as,for example, personal digital assistants, smartphones, laptop computers,web browsers, etc.

In the above exemplary embodiments, a number of software modules weredescribed. As those skilled will appreciate, the software modules may beprovided in compiled or un-compiled form and may be supplied to the dualFAP or to the mobile device as a signal over a computer network, or on arecording medium. Further, the functionality performed by part or all ofthis software may be performed using one or more dedicated hardwarecircuits. However, the use of software modules is preferred as itfacilitates the updating of the dual FAP (HeNB part/AP part) and themobile device in order to update their functionalities.

In the above exemplary embodiments, the concurrent LTE and non-LTEcommunications are carried out by the same dual FAP. However, whilst theabove exemplary embodiments have particular benefit for alleviating indevice coexistence interference issues, it will be appreciated that someaspects of the invention may be employed to alleviate interference insituations where one base station communicates using the LTE RAT andanother but separate base station/access point in the vicinitycommunicates using a non-LTE radio technology. Further, it will beappreciated that the above mechanisms may also be applicable to a basestation operating in an unlicensed spectrum, such as a base station (ofa dual FAP) conforming to a future release of the LTE Advanced (LTE-A)set of standards (in addition to the LTE and/or ISM standards).

In the above exemplary embodiments, the dual FAP 5 comprises separateLTE and ISM baseband circuits 50-1 and 50-2. Each baseband circuit 50-1and 50-2 is coupled to its own radio frequency transceiver 51-1 and 51-2and uses its dedicated antenna 53-1 and 53-2. It will be appreciatedthat the baseband circuits 50-1 and 50-2, the transceivers 51-1 and51-2, and the antennas 53-1 and 53-2 might be combined in one component.Alternatively, the dual FAP 5 might employ separate circuits and/orseparate transceivers and/or separate antennas for each type of RAT thatit supports. For example, although both Bluetooth and Wi-Fi are ISMradio access technologies, these standards may be implemented usingseparate circuits and/or separate transceivers and/or separate antennas.It is also possible that a given RAT requires more than one antenna oruses a separate transmitter and/or receiver part.

The exemplary embodiments have been described using Wi-Fi transceiversas an example of a non-LTE (in this case, ISM) radio technology.However, the mechanisms described herein can be applied to other non-LTEradio technologies (e.g. other ISM technologies, such as Bluetooth, NFC,etc. and/or GPS technologies).

For example, the mechanisms may be applied to the following ISMtechnologies:

-   -   Bluetooth devices;    -   Cordless phones;    -   Near field communication (NFC) devices;    -   Wireless computer networks, such as HIPERLAN, Wi-Fi (IEEE        802.11);    -   Wireless technologies based on IEEE 802.15.4, such as ZigBee,        ISA100.11a, WirelessHART, and MiWi.

The mechanisms may also be applied to the following Global NavigationSatellite System (GNSS) technologies:

-   -   Global or regional satellite navigation systems, such as GPS,        GLONASS, Galileo, Compass, Beidou, DORIS, IRNSS, and QZSS;    -   Global or regional Satellite Based Augmentation Systems, such as        Omnistar, StarFire, WAAS, EGNOS, MSAS, and GAGAN;    -   Ground based augmentation systems, such as GRAS, DGPS, CORS, and        GPS reference stations operating Real Time Kinematic (RTK)        corrections.

In the above exemplary embodiment described with reference to FIG. 9b ,the HeNB part is described to adjust/set its own transmit power (DL) andthe transmit power (UL) for the mobile devices in the HeNB's cell basedon information obtained from the AP part. It will be appreciated thatthe HeNB part may be configured to adjust the value of ‘P_(eMax)’ asdescribed in 3GPP TS 36.331, based on an offset that is dependent on thechannel information/power used by the Wi-Fi AP part (obtained in stepS911). It will also be appreciated that the so calculated P_(eMax) maybe used for calculating the value of ‘P_(CMAX)’, which is defined in3GPP TS 36.101.

Further, the HeNB part may be configured to derive the power(‘P_(PUSCH)’) used on the physical uplink shared channel (PUSCH), e.g.using the following formula (in accordance with 3GPP TS 36.213):P _(PUSCH)(i)=min{P _(CMAX),10 log₁₀(M _(PUSCH)(i))+P_(O_PUSCH)(j)+α(j)·PL+Δ _(TF)(i)+f(i)}

The HeNB part may also be configured to derive the power (‘P_(PUSCH)’)used on the physical uplink control channel (PUCCH), e.g. using thefollowing formula (in accordance with 3GPP TS 36.213):

${P_{PUCCH}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)}\mspace{644mu}} \\{P_{0{\_{PUCCH}}} + {PL}_{c} + {h( {n_{CQI},n_{HARQ},n_{SR}} )} + {\Delta_{F\_{PUCCH}}(F)} + {\Delta_{TxD}(F)} + {g(i)}}\end{Bmatrix}}$

However, it will be appreciated that, irrespective of whether or not theAP part has provided its channel information/transmit power informationto the HeNB part, the HeNB part may be configured to autonomouslyperform power control/adjustment, i.e. without taking into account anyinformation received from the Wi-Fi AP part. This may be the case, forexample, if LTE service is prioritized over Wi-Fi service. It will beappreciated that the HeNB part may perform power control purely based onNMM measurements/UE reports.

In the above exemplary embodiments described with reference to FIGS. 8ato 9a, and 10a to 11, the HeNB part is described to initiate proceduresby sending an appropriately formatted message to the AP part (e.g. arestrict channel request, a power info request, entering/exiting ESMnotifications, etc.) or to the mobile device (e.g. a steering command).However, it will also be appreciated that similar actions may also betriggered by the AP part (instead of the HeNB part) by the AP partsending an appropriately formatted message to the HeNB part (or themobile device).

It will be appreciated that if the HeNB's current frequency isexperiencing an IDC interference (and assuming that the HeNB part isable to use a different frequency), then the HeNB part may be configuredto perform a so-called carrier frequency reselection procedure. Carrierfrequency reselection may be required if excessive interference isexperienced by the HeNB part either due to co-existing transmissions bythe AP part and/or neighbouring HeNB parts/Wi-Fi AP parts. In this case,the HeNB part may be configured to perform an appropriate NMM operationand use any information received from the AP part (e.g. over theinternal interface) about the AP's channels and the associatedtransmission powers in order the HeNB part to be able to assess theinterference situation and evaluate which carrier frequency it needs toreselect. Additionally, on changing (reselecting) the carrier frequency,the HeNB part may be configured to inform the co-existing Wi-Fi AP partabout its newly selected operating frequency so that any restriction canbe lifted by the AP part if the new HeNB part operating frequency isaway from the lower portion of FDD band 7, the upper portion of TDD Band40, and/or the lower portion of Band 41.

In the above exemplary embodiment described with reference to FIGS. 10aand 10b , the HeNB part is described to control the AP's restrictions touse certain parts of the ISM band by sending an appropriate notificationabout its current energy saving state (i.e. whether or not its LTEtransmissions are suspended). In a modification of this exemplaryembodiment, it will be appreciated that the HeNB part may also notifythe co-located AP part whether or not its LTE radio transmissions areturned off (instead of being suspended). For example, the HeNB part maybe required to turn off its LTE transceiver in response to a command(e.g. a ‘Radio Transmission OFF’ command) received from an HeMS entityand/or the like. The HeNB part may also be required to turn off its LTEtransceiver (e.g. automatically or upon user action) in case of an HeNBfailure and/or an HeNB location change. It will be appreciated that insuch cases the procedures described with reference to FIGS. 10a and 10bmay be adapted to inform the AP part about the turning off and asubsequent turning on of the HeNB's LTE transceiver, similarly to theindications sent upon the HeNB part entering/exiting the energy savingmode.

In the above exemplary embodiments, the interference issues have beendescribed with respect to one device (e.g. dual FAP) operating both theLTE and the non-LTE transceivers. However, it will be appreciated thatthe exemplary embodiments are applicable to interference issuesinvolving multiple devices, e.g. one device operating an LTE transceiverand another device operating an ISM transceiver. The exemplaryembodiments are also applicable to dual FAPs which do not have anyongoing LTE transmissions (but e.g. their ISM transmissions suffer frominterference by another device).

The at least one operation to alleviate interference may comprise atleast one of:

-   -   an operation to restrict a channel operated by at least one of        said base station module and said access point module;    -   an operation to restrict a transmit power usable by at least one        of said base station module and said access point module;    -   an operation to schedule communications via at least one of said        base station module and said access point module;    -   an operation to reselect a carrier frequency used by at least        one of said base station module and said access point module;        and    -   an operation to steer traffic to/from at least one of said base        station module and said access point module.

In one possibility, the co-operation to alleviate interference maycomprise one of said base station and said access point modules sendinga request, via said interface, for the other of said base station andsaid access point modules to restrict a channel operated by the otherone of said base station and said access point modules.

In one possibility, when said other of said base station and said accesspoint modules restricts said channel, in accordance with said request,said at least one operation to alleviate interference may comprise saidother of said base station and said access point modules restrictingcommunications via said channel in response to said request.

In one possibility, one of said base station and said access pointmodules may be configured: i) for entering an energy saving mode inwhich transmission in at least one channel is suspended; and ii) when insaid energy saving mode, for leaving said energy saving mode and toresume said transmission in said at least one channel. In this case, theother of said base station and said access point modules may beconfigured: i) when said one of said base station and access pointmodules enters said energy saving mode, to lift a communicationrestriction with respect to said at least one channel; and ii) when saidone of said base station and access point modules leaves said energysaving mode, to perform at least one operation, to alleviateinterference, comprising imposing or re-imposing a communicationrestriction with respect to said at least one channel.

In one possibility, when said other of said base station and said accesspoint modules does not restrict said channel, in accordance with saidrequest, it may send as part of said co-operation, via said interface, aresponse to said request. In this case, said one of said base stationand said access point modules may be configured to perform, based onsaid response, an operation, to alleviate interference, comprisingrestricting communications via at least one channel operated by said oneof said base station and said access point modules.

In one possibility, the other of said base station and said access pointmodule may be configured to, when said other of said base station andsaid access point modules does not restrict said channel, in accordancewith said request, send as part of said co-operation, via saidinterface, a response to said request; and said one of said base stationand said access point modules may be configured to perform, based onsaid response, an operation, to alleviate interference, comprisingrestricting a transmit power of said one of said base station and saidaccess point modules.

In one possibility, said other of said base station and said accesspoint module may be configured to, when said other of said base stationand said access point modules does not restrict said channel, inaccordance with said request, send as part of said co-operation, viasaid interface, a response to said request; and said one of said basestation and said access point modules may be configured to perform,based on said response, an operation, to alleviate interference,comprising scheduling communications via said one of said base stationand said access point modules to avoid said interference.

In one possibility, the co-operation may comprise said base stationmodule obtaining, via said interface, information identifying a loadlevel of said access point module, and said at least one operation toalleviate interference may comprise at least one operation based on saidinformation identifying a load level of said access point module. Inthis case, the at least one operation to alleviate interference maycomprise steering communication traffic to/from at least one of saidbase station module and said access point module based on saidinformation identifying a load level of said access point module.

In one possibility, the co-operation may comprise said base stationmodule obtaining, via said interface, information identifying at leastone channel operated by said access point module, and said at least oneoperation to alleviate interference may comprise at least one operationbased on said information identifying at least one channel operated bysaid access point module. In this case, the at least one operation basedon said information identifying at least one channel may comprisereselecting a carrier frequency used by said base station module basedon said information identifying at least one channel operated by saidaccess point module whereby to alleviate interference.

In one possibility, the co-operation may comprise said base stationmodule obtaining, via said interface, information identifying atransmission power associated with at least one channel operated by saidaccess point module, and said at least one operation to alleviateinterference may comprise at least one operation based on saidinformation identifying a transmission power. In this case, the at leastone operation based on said information identifying a transmission powermay comprise reselecting a carrier frequency used by said base stationmodule based on said information identifying a transmission power. Inone possibility, the at least one operation to alleviate interferencemay comprise applying at least one modified transmission power level forcommunications between said base station module and said one or moremobile communication devices based on said information identifying atransmission power.

The base station module and the access point module may be mountedwithin a common housing. The communication apparatus may comprise a dualmode femto access point. The base station module may comprise a homebase station operating in accordance with the long term evolution (LTE)family of standards. The access point module may comprise an accesspoint operating in accordance with the 802.11 family of standards by theInstitute of Electrical and Electronics Engineers (IEEE).

Various other modifications will be apparent to those skilled in the artand will not be described in further detail here.

Glossary of 3Gpp Terms

-   AP Access Point-   BT Bluetooth-   DRX Discontinuous Reception-   eNB Evolved NodeB-base station-   E-UTRA Evolved UMTS Terrestrial Radio Access-   E-UTRAN Evolved UMTS Terrestrial Radio Access Network-   FAP Femto Access Point-   FDM Frequency Division Multiplexing-   GNSS Global Navigation Satellite System-   GPS Global Positioning System-   GW Gateway-   HeMS Home eNodeB Management System-   HeNB home base station-   IDC In Device Coexistence-   ISM Industrial, Scientific and Medical (radio bands)-   LTE Long Term Evolution (of UTRAN)-   MME Mobility Management Entity-   RAT Radio Access Technology-   RRC Radio Resource Control-   RRM Radio Resource Management-   SeGW Security Gateway-   SIR Signal to Interference Ratio-   TDM Time Division Multiplexing-   UE User Equipment-   DL Downlink—link from base station (dual FAP) to mobile device-   UL Uplink—link from mobile device to base station (dual FAP)

This application is based upon and claims the benefit of priority fromUK patent application No. 1410538.1, filed on Jun. 12, 2014, thedisclosure of which is incorporated herein in its entirety by reference.

The invention claimed is:
 1. An eNB comprising: a transceiver configuredto communicate with a user equipment (UE) and configured to provide LongTerm Evolution (LTE) connectivity for the UE, the UE configured to useradio resources of an LTE network and a wireless local area network(WLAN); and a controller configured to: request, over a dedicatedinterface, to a communication device for providing a connectivitybetween the UE and the WLAN, a load information and a channelutilization time information of the WLAN; receive, over the dedicatedinterface, the requested load information and the requested channelutilization time information from the communication device; and receive,from the communication device over the dedicated interface, WLANinformation identifying at least one channel or frequency band of theWLAN.
 2. The eNB according to claim 1 wherein the load informationcomprises information identifying a number of UEs served by thecommunication device.
 3. The eNB according to claim 1 wherein the loadinformation comprises information identifying an available capacity ofthe communication device.
 4. A communication apparatus comprising: atransceiver configured to communicate with a user equipment (UE) andconfigured to provide a wireless local area network (WLAN) connectivityfor the UE, the UE configured to use radio resources of a Long TermEvolution (LTE) network and the WLAN; and a controller configured to:receive, over a dedicated interface, from an eNB for providing aconnectivity between the UE and the LTE network, a request for a loadinformation and a channel utilization time information of the WLAN;send, over the dedicated interface, the load information and the channelutilization time information to the eNB in accordance with the request;and send, to the eNB over the dedicated interface, WLAN informationidentifying at least one channel or frequency band of the WLAN.
 5. Amethod performed by an eNB comprising a communication module configuredto communicate with a user equipment (UE) and configured to provide LongTerm Evolution (LTE) connectivity for the UE, the UE configured to useradio resources of an LTE network and a wireless local area network(WLAN), the method comprising: requesting, over a dedicated interface,to a communication device for providing a connectivity between the UEand the WLAN, a load information and a channel utilization timeinformation of the WLAN; receiving, over the dedicated interface, therequested load information and the requested channel utilization timeinformation from the communication device; and receiving, from thecommunication device over the dedicated interface, WLAN informationidentifying at least one channel or frequency band of the WLAN.
 6. Amethod performed by a communication device configured to communicatewith a user equipment (UE) and configured to provide a wireless localarea network (WLAN) connectivity for the UE, the UE configured to useradio resources of a Long Term Evolution (LTE) network and the WLAN, themethod comprising: receiving, over a dedicated interface, from an eNBfor providing a connectivity between the UE and the LTE network, arequest for a load information and a channel utilization timeinformation of the WLAN; sending, over the dedicated interface, the loadinformation and the channel utilization time information to the eNB inaccordance with the request; and sending, to the eNB over the dedicatedinterface, WLAN information identifying at least one channel orfrequency band of the WLAN.